The invention relates to a method and to a device for open-loop/closed-loop control of a robot manipulator, which includes a sensor for detecting a mechanical interaction with an environment. The invention further relates to a robot having such a device, as well as to a computer system, a digital storage medium, a computer program product, and a computer program.
Methods and devices for open-loop/closed-loop control of a robot manipulator are known. Thus, from DE 102010048369 A1, for example, a method and a device for safe open-loop control of at least one robot manipulator is known, wherein at least one safety functionality is monitored. A safety functionality in the sense of DE 102010048369 A1 preferably represents precisely an elementary physical variable or functionality, for example, the state or output of a switch, of a sensor, or of a computation unit. An elementary physical variable or functionality can also be multidimensional and, accordingly, it can also be formed by several switches, sensors, and/or computation units. Thus, for example, an external force acting on the manipulator, particularly at the Tool Center Point (TCP), can represent an elementary physical variable or functionality, which accordingly can be represented by a “force at the TCP” safety functionality, and which can be monitored, for example, for the presence of a threshold value or to determine whether a threshold value has been exceeded or not reached.
A safety functionality in the sense of DE 102010048369 A1 can be a contact detection, in particular by detection of a one-dimensional or multi-dimensional contact force, a collision detection, in particular by detection of forces in manipulator articulations or drives, an axial area monitoring, a path accuracy, in particular a tube around the Cartesian trajectory, a Cartesian workspace, a safety zone, a braking ramp, a braking before one or more safety zones or spatial boundaries, a manipulator configuration, a tool orientation, an axial speed, an elbow speed, a tool speed, a maximum external force or a maximum external torque, a distance with respect to the environment or a person, a retention force, or the like.
Safety functionalities are preferably monitored using a safe technology, in particular redundantly and preferably in diverse manners or with a safety protocol. For this purpose, it is preferable that one or more parameters, for example, outputs of sensors or calculation units, are detected independently of a work controller of the respective manipulator, and, in particular after further processing in a calculation unit, for example, after coordinate transformation, are monitored to determine whether threshold values have been exceeded. In a proposed embodiment, if at least one of the parameters to be detected cannot be detected reliably, for example, due to sensor failure, the corresponding safety functionality responds in a proposed embodiment.
In DE 102010048369 A1, it is then proposed to implement the safety monitoring as a state machine, which can alternate between two or more states in each of which one or more of the above-explained safety functionalities, which are predetermined for this state, are monitored. The implementation can be converted, in particular, by a corresponding programming and/or a corresponding program execution, in particular in the form of a so-called virtual state machine.
Moreover, from DE 102013212887 A1, a method for open-loop control of a robot device is known, which includes a movable robotic manipulator, in which a movement speed and/or movement direction of the manipulator is monitored and optionally adapted taking into consideration medical injury parameters and a robot dynamics. According to DE 102013212887 A1, the manipulator and/or effector can move along a predetermined path or at a predetermined movement speed. The medical injury parameters can contain information representative of an effect of a collision between the manipulator and a human body, and they can be used as input variable in the method. The effect can be an injury of a human body. A movement speed and/or movement direction of the manipulator can be adapted, for example, by reduction, in order to reduce or prevent an injury. A robot dynamics can be a physical, in particular a kinetic dynamics. A robot dynamics can be a dynamics of a rigid and resilient many-body system. For monitoring and optionally adapting the movement speed and/or movement direction of the manipulator, a collision mass, a collision speed, and/or a collision contact geometry of the manipulator can be taken into consideration. A collision mass, a collision speed, and/or a collision contact geometry of the manipulator can be used in the method as input variable. An expected collision mass, collision speed, and/or collision contact geometry of at least one predetermined relative point of the manipulator can be taken into consideration. Here, the expectation can relate to an assumed or known location of a human in the work area of the robot device, taking into consideration the predetermined movement path. In order to monitor and optionally adapt the movement speed and/or movement direction of the manipulator, characteristic values can be used, which represent, on the one hand, a relation between collision mass, collision speed, and/or collision contact geometry of the manipulator, and, on the other hand, medical injury parameters. The characteristic values can be represented in mass-speed diagrams for different contact geometries and different injury types. The contact geometries can be simple representative geometries. A contact geometry can be wedge-shaped. The contact geometry can be wedge-shaped with different angles. A contact geometry can be spherical. The contact geometries can be spherical with different diameters. An injury type can be an injury of closed skin of a body. An injury type can be an injury of muscles and tendons of a body.